In a Thin Film Transistor Liquid Crystal Display device (TFT-LCD), each pixel unit is driven by one or a plurality of TFTs integrated in the vicinity thereof, thereby realizing high-speed, high-brightness, and high-contrast display effects. Therefore, the performance of the TFT has a decisive influence on the quality of a display panel.
Generally, a TFT in the field of liquid crystal display is expected to have a relatively large activation current. That is, the voltage of the pixel unit is to be charged to a desired range in a short period of time. In a high-resolution display device, the pixel units are smaller and more intensively arranged, and each pixel has a shorter charge time when there is no variation in refresh rate thereof. Therefore, the above requirement is particularly essential in such display applications.
In the prior art, the activation current of a TFT is generally increased through increase in a width-to-length ratio of a TFT channel. For example, a U-shaped TFT can be used. However, the TFT of such a structure will increase the difficulty in a manufacturing procedure thereof, which renders it uneasy to ensure manufacture accuracy and will generate unnecessary parasitic capacitance.